Centrifugally armed percussion fuze



Jan. 19, 1960 w. GUERNE CENTRIFUGALLY ARMED PERCUSSION FUzE 2 Sheets-Sheet 1 Filed April 2, 1958 /NvE/v TOR WIIIILIAM GUERNE gan( 11ml A TTORNEY Jan. 19, 1960 w. GUERNE 2,921,527

CENTRIFUGALLY ARMED PERCUSSION FuzE Filed April 2, 1958 2 sheets-sheet 2 NVE TUR WILLIAM GUERN 'OGQ @mf ATTORNEY 2,921,527 Patented Jan. 19, 1960 This invention relates to centrifugally-armed percussion fuzes, i.e. to fuzes adapted to be used in connection with rotatable or spin-stabilized projectiles and which are rendered sensitive to percussion by centrifugal forces developed by rotation of the projectile about its own axis when it has been launched. The invention more particularly concerns fuzes for projectiles of smaller sizes, such as those whose calibre is comprised between 20 and 50 millimetres.

For the purpose of an increased safety of such fuzes it has already been proposed to provide therein a movable or oscillating element adapted to oscillate about an axis Vtransverse to the fuze axis, the said element having an open diametral cavity containing an initiating pyrotechnic charge or primer adapted to ensure ignition of another pyrotechnic charge, such as a booster or relay charge, under the action of impact, which movable element is disposed in front of the charge to be ignited and is so arranged as to rotate under the action of centrifugal forces from an inoperative position at which the cavity is at an angle to the fuze axis and therefore opens laterally with respect to the charge to be ignited, to an operative position at which the said cavity is in line with the fuze axis and opens just in front of the charge to be ignited.

It is an object of the present invention to improve this kind of centrifugally-armed percussion fuzes, and more particularly to obtain a safer ignition on impact.

In accordance with this invention, in a centrifugally armed percussion fuze of the kind above-referred to, means are provided to retain the oscillating element at an advanced position within the fuze against the action of means which urge the said oscillating element backwardly, the said retaining means becoming inoperative when the oscillating element has rotated to its operative position under the action of centrifugal forces, whereby the said oscillating element is urged to and retained at a rearmost position at which it is substantially in contact with the charge to be ignited, in such a manner that there is formed a substantially continuous flash passage between the initiating charge and the charge to be ignited.

There is'conveniently interposed between the oscillating element and the charge to be ignited a laterally movable shield adapted to retain the said oscillating element at its advanced position within the fuze, means being provided whereby the said shield is displaced aside by the oscillating element when the latter rotates from its inoperative position to its operative position under the action of centrifugal forces.

The movable shield may be provided on its front side with a projection adapted to engage a notch provided in the periphery of the oscillating element when the latter is at its inoperative position.

The oscillating member is preferably disc-shaped and it ,is formedv with lateral journals which are slidably housed within-longitudinally extending guiding slots pro- -the body of the fuze.

In the annexed drawings: Fig. 1 is a partial axial section of a centrifugally-armed percussion fuze according to the present invention, the

parts being illustrated at the inoperative or safe position of the oscillating element.

Fig. 2 is an axial section similar to Fig. 1, but the parts being illustrated at the armed position of the fuze.

Fig. 3 is a section at right angles with respect to Fig. 2, also showing the parts at the armed position of the fuze.

In the example illustrated the fuze is adapted to ignite the relay charge 1 of a detonator 2 secured onto the body 3 of the fuze. The fuze itself comprises a striker 4 and an oscillating element comprising a disc-shaped member 5 formed with opposed journals 6, the said disc having an inner diametral housing 7 open at both ends and adapted to receive aninitiating or primer charge 8 which on impact ensures the ignition of the relay or booster charge 1. This charge may be formed of a single pyrotechnic composition or of a number of such compositions of different sensitivities.

The disc-shaped member is rotatably mounted between two cheeks 9 which may be in one with a plug 10 in which is disposed the relay charge 1, the said plug being screwed into the rear end of the fuze body 3.

It`will be appreciated that when the projectile which carries the fuzerotates about its own axis, the disc-shaped member 5 tends to assume under the action of centrifugal forces such a position that its polar moment of inertia with respect to the axis of rotation, i.e. to the fuze axis, be at a maximum. This position corresponds to the position illustrated in Fig. 2, wherein the axis of the diametral housing 7 which contains the initiating charge is coincident with the axis of the fuze, striker 4,

initiating charge 8 and relay charge 1 then being in line.

Means releasable under the action of centrifugal forces are provided to lock the disc-shaped member 5 until the projectile is launched, at the position illustrated in Fig. 1 for which the axis of housing '7 is at an angle to the axis of the fuze, the rear end of the said housing being thus laterally spaced from relay charge 1. In the example shown these means comprise a radially expandable split ring 11 which surrounds both disc-shaped member 5 and cheeks 9 and which is engaged into slots 12 and 13 provided in the periphery of the said member and in the cheeks.

Between disc-shaped member 5 and plug 10 there is disposed a movable cover or shield 14 which is adapted to close the fore end of the bore which contains relay charge 1, the said shield preventing an untimely ignition of the relay charge before the projectile is tired. This movable -shield 14 is actuated by disc-shaped member 5 itself in such a manner that when the latter moves from its inoperative position of Fig. 1 to its operative position of Fig. 2, it displaces laterally the said shield. In the arrangement shown this is obtained by forming the upper or front side of movable shield 14 with a projection 14a which is engaged into a notch 15 provided in the periphery of disc-shaped member, in the portion thereof which is in front of relay charge 1 when the said disc-shaped member is at its inoperative position of Fig. 1.

The disc-shaped member 5 is preferably mounted between cheeks 9 in such a manner that it may move backwards when movable shield 14 has been displaced laterally, for taking-up the clearance corresponding to the thickness of the said shield. This may be obtained by disposing the journals 6 of the disc-shaped member in longitudinally extending slots 16 parallel to the fuze axis. Conveniently these slots 16 open forwardly in order to facilitate mounting of the fuze and they extend rearwardly to permit the disc-'shaped member 5 to come into contact with plug 10. Means are further provided for maintaining the said disc-shaped member against the plug during the slowing down step o f the projectile after it has been launched, when the said member would tend to move forwardly within the fuze under the action of its ownv inertia. YThese means may conveniently be formedof two helicoidal springs 17 disposed in slots 16,

the said springs acting on journals 6 by their rearvendsy 1 while their front ends rest against the body of the fuze.

It will b e appreciated that owing to springs 17, or to any other equivalent means adapted to maintain discshaped member 8 against plug 10 when the projectile has been launched, the ignition ofthe relay charge on impact is more safely ensured since the initiating charge 8 is as near as possible to the said relay charge, the flash passage between both charges being moreover continuous, without any practical possibility of lateral discharge.

What I claim is: 1

LA -centrifugally armed percussion fuze for spinstabilized projectiles comprising impact sensitive firing means at the fore end of said fuze; a charge to be ignited at the rear end of said fuze; an axially lmovable intermediate element disposed between said ring means and said charge to be ignited, said intermediate element being rotatable about an axis transverse to the axis of said fuze, said intermediate element being formed with a ends and adapted to receive a primer charge, and said intermediate element being so formed that under the 'action'of spin-induced centrifugal forces it tends to rotate from an inoperative angular position at which the axis of said cavity is at an angle to the axis of said fuze tosan operative angular position at which the axis of said cavity is in line with the axis of said fuze, with said charge to be ignited and with said firing means; urging means to urge said intermediate element backwardly towards said charge to be ignited; a protective shield member interposed b'etween said charge to be ignited and said intermediate element at the inoperative angular position thereof, said shield member retaining said intermediate element at an axially advanced position within said fuze and said shield member being movable transversely of the axis of said fuze; and means to displace laterally said protective shield member when said intermediate element rotates from its inoperative angular position to its operative angular position, to cause said intermediate element to move backward'ly under the action of said urging means to come substantially into engagement with said charge to be ignited. 1

2. In a fuze as claimed in claim l, means on said intermediate element to displace laterally said protective shield member when said intermediate element rotates from its inoperative angular position to its operative angular position.

3. ln a fuze as claimed in claim l, said intermediate element and said protective shield member being formed with interengaging portions which cause lateral displacement of said protective shield member when said intermediate element rotates from said inoperative angular position to said operative angularA position.

4. A centrifugally armed percussion fuze for spinstabilized projectile comprising impact sensitive ring means at the fore end of said fuze; a charge to be ignited at the'rear. end ofY said fuze; an axially movable substantially circular intermediatey element disposed betweenfsaid firing means andY said charge to'be ignited, said intermediate element being rotatable about an axis transverse' to the axis of said fuze, said intermediate element being' formed with a transverse substantially diametral cavity opening at both ends and adapted to receive a primer `transverse substantially diametral cavity opening at both charge, said intermediate element being so-forrned that under the action of spin-induced centrifugal forces it tends to rotate from an inoperative angular position at which the axis of said cavity is at an angle to the axis of said fuze to an operative angular position at which the axis of said cavity isY in line with the axis of said fuze, with said charge to be ignited and with said iiring means, and said intermediate element having a'peripheral notch extending parallel to the axis of said element and substantially situated at the rearmost end of said element when same is at its inoperative angular position; urging means to urge said intermediate element backwardly towards said charge to be ignited; a protective shield member interposed between said charge to be ignited and said intermediate element at the inoperative angular position thereof, said shield member retaining said intermediate element at an axially advanced position within said fuze, said shield member being movable transversely of the axis of said fuze, and said shield member being formed on its front side with a projection which engages the peripheral notch of s aid intermediate element when same is at its inoperative angular position to c ause said shield to be moved aside when said intermediate element rotates from its inoperative angular position to its operative angular position and to permit said intermediate element to move Vbackwardly under the action of said urging means to come substantially into engagement with `said charge to be ignited.

5. in a fuze as claimed in claim 4, said intermediate `element being in the form of a disc-shaped member provided with lateral journals transverse to the axis of said a rear en d; a striker at the fore end of said body; a plug v at therear end of said body to receive a booster charge, said plug being formed with an axial bore opening on the front side thereof and said plug having a substantially transverse slot in its front side; an axially movable substantially disc-shaped intermediate element rotatable about an axis transverse to the axis of said fuze between said striker and said booster charge, said intermediate element being formed with a transverse diametral bore opening at both ends to receive a primer charge adapted to be ignited by said striker and to ignite in turn said booster charge, said intermediate element being so formed that under the action of spin-induced centrifugal forces it tends to rotate from an inoperative angular position at which the axis of said diametral bore is at an angle to the axis of said fuze to an operative angular position Y position; axial journals on both sides'of said disc-shaped intermediate element to guide same axially; longitudinally extending guiding means for said journals within said body; spring means acting on said journals to urge said intermediate element backwardly with respect to the. fuze; a protective shield member slidably disposed in the transverse slot of said plug to cover the opening of the bore of said plug and to retain said intermediate ele-V ment at an axially advanced position Within said fuze against the action of said spring means, said shield member being formed on its front side with a projection which engages the peripheral notch of said, intermediate element when same is at its inoperative angular position to cause said shield to be moved aside when said intermediate element rotates from its inoperative angular position to its operative angular position and to permit said intermediate element to move backwardly under the action of said spring means to come into contact with the opening of the bore of said plug within the transverse slot thereof.

7. In a fuze as claimed in claim 6, centrifugally releasable means to retain said intermediate element against rotation at is inoperative angular position.

8. In a. fuze as claimed in claim 6, said guiding means comprising longitudinally slotted members disposed within said body on each side of said intermediate element to slidably receive said journals and to form guiding means thereof.

9. In a fuZe as claimed in claim 6, said plug being formed with extensions disposed on each side of said intermediate element and said extensions being 1ongitudinally slotted to slidably receive said journals and to form guiding means thereof.

References Cited in the file of this patent UNITED STATES PATENTS 2,709,962 Funk .Tune 7, 1955 2,824,518 Piskorski Feb. 25, 1958 FOREIGN PATENTS 1,134,838 France Dec. 10, 1956 UNITED STATES PATENT OFFICE or common Patent No 2,921,527 January 19, 1960 William Guerne Y It is hereby certified that error appears in the above numbered patent requiring Correction and thatl the said Letters Patent should read alsl corrected below.a

In the heading to the printed specification,l line '7, the priority date, for "April 7, 1957 read April 1957 -n Signed and sealed this i 9th dey of August 1960o (SEAL) Attest:

KARL H' AXUNE ROBERT c. wA'rsoN t'bestng Officer Conmissoner of Patents UNITED STATES PATENT OFFICE CERTIFICATE or CORRECTION Patent No., 921,527 A January 19, 1960 william Guerne It is hereby Certified that error appears in the above numbered patent requiring correction and that4 the said Letters Patent should read as Corrected below.

In the heading to the printed specification, line 7, the priority date,` for "April 7, 1957*" read April 1957 -wo Signed and sealed this 9th dey of August 1960;7

(SEAL) Attest:

KARL H AXLINE 4 e ROBERT C. wATsoN Attesting Offer lCoxrlniaasioner of Patents 

